Oxygen lance method and big acetylene-oxygen blow-pipe method were treated. Both are the first trials in Japan, so the authors started their work with making special apparatuses and arrangements. A four-ton steel ingot was the test piece to be cut by the former method. The size of steel pipe for the lance, gas (oxygen) pressure and consumption, time needed for cutting, etc. were studied. The report on the latter method is to be made later.
In flash-butt welding, heat treatment after operation has a great significance, because these is a hazard of localized overheating from a great deal of heat produced in a short duration of time. In Report I, the authors concluded after having carried out heat treatment at various temperatures of flash-butt welded rail steels and examined mechanical properties and microstructures that high temperature treatment was desirable. In the present Report, the results of bending and fatigue test are given. According to the tests, it is confirmed that consideration of safety for durability also requires the high temperature treatment.
Pb-Sn alloys of various compositions were used as soft solders for the research Each 0.1 g of solder was put on thin copper plate which preheated to a desired temperature in the thermostat 0.5 c c of zinc-chloride solution or other fluxes was applied on the solder by pipette. Then the spread area of solder was determined by the planimeter. (1) A maximum spread area was found at the solder of eutectic composition. (2) In all kinds of compositions of the solders a maximum spread area was obtained at 260°C when the saturated solution of zinc-chloride was used as a flux. Some interesting problems about the soft soldering was found in the experiment and described in this paper.
The two-dimensional heat distribution under quasi-stationary state due to linear moving heat source of infinate plate can be expressed : u=qe-xv/2h2/2πbcph2K0(2√ γ) ; where γ=(4a2h2+v2)/16h4(x2+y2) And the isotherm for it may be approximately expressed as follows : C-a0Y=√R2+X2+log|√R2+1-1|, Y=√R2-X2, where α0=vα1/√4a2h2+v2, β0=4h2β1/√4a2+h2+v2;α1=0.96, β1=0.16, and C=integral constant. As far as the immediate neighbourhood of heat source is concerned, this isotherm may be substituted by ellipse which can be represented by the following equation: (1-2α′2C)x2+y2+2α0′Cx=0; α0′=α′v/2h2, α=2.5 Further the graphical method for defining the isotherm is described (Fig. 8) with regard to the geometrical significance of this expression. The main charrcteristics of the isotherm clarified through the graphical method are as follows: (i) The isotherm in this case takes form of an egg top-heavy in the direction of welding progress. (ii) In the neighbourhood of heat source, all of these isotherms approach circles. (iii) In the ZONE sufficiently detached from heat source, these curves tend to be the more flattened under the higher speed of welding. On the other hand, study of the change of tangent will contribute to fundamental theory of "the formation of beardlike Lüders' lines clustered in series in the part of base metal adjacent to welding bead."